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https://www.readbyqxmd.com/read/28634062/site-directed-mutagenesis-of-gh10-xylanase-a-from-penicillium-canescens-for-determining-factors-affecting-the-enzyme-thermostability
#1
Yury A Denisenko, Alexander V Gusakov, Aleksandra M Rozhkova, Dmitry O Osipov, Ivan N Zorov, Veronika Yu Matys, Igor V Uporov, Arkady P Sinitsyn
In order to investigate factors affecting the thermostability of GH10 xylanase A from Penicillium canescens (PcXylA) and to obtain its more stable variant, the wild-type (wt) enzyme and its mutant forms, carrying single amino acid substitutions, were cloned and expressed in Penicillium verruculosum B1-537 (niaD-) auxotrophic strain under the control of the cbh1 gene promoter. The recombinant PcXylA-wt and I6V, I6L, L18F, N77D, Y125R, H191R, S246P, A293P mutants were successfully expressed and purified for characterization...
June 17, 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/28632140/thermal-stability-and-rheological-properties-of-the-non-stick-caf1-biomaterial
#2
Yakup Ulusu, Gema Dura, Helen Waller, Matthew Benning, David Fulton, Jeremy Lakey, Daniel Thomas Peters
The ability to culture cells in three dimensions has many applications, from drug discovery to wound healing. 3D cell culture methods often require appropriate scaffolds that mimic the cellular environments of different tissue types. The choice of material from which these scaffolds are made is of paramount importance, as its properties will define the manner in which cells interact with the scaffold. Caf1 is a protein polymer that is secreted from its host organism, Yersinia pestis, to enable escape from phagocytosis...
June 20, 2017: Biomedical Materials
https://www.readbyqxmd.com/read/28629346/a-hyper-thermostable-%C3%AE-amylase-from-pyrococcus-furiosus-accumulates-in-nicotiana-tabacum-as-functional-aggregates
#3
Hong Zhu, L Bruce Reynolds, Rima Menassa
BACKGROUND: Alpha amylase hydrolyzes α-bonds of polysaccharides such as starch and produces malto-oligosaccharides. Its starch saccharification applications make it an essential enzyme in the textile, food and brewing industries. Commercially available α-amylase is mostly produced from Bacillus or Aspergillus. A hyper-thermostable and Ca (2++) independent α-amylase from Pyrococcus furiosus (PFA) expressed in E.coli forms insoluble inclusion bodies and thus is not feasible for industrial applications...
June 19, 2017: BMC Biotechnology
https://www.readbyqxmd.com/read/28628984/high-level-expression-of-recombinant-thermostable-%C3%AE-glucosidase-in-escherichia-coli-by-regulating-acetic-acid
#4
Xuejia Shi, Jingcong Xie, Shiyong Liao, Tao Wu, Lin-Guo Zhao, Gang Ding, Zhenzhong Wang, Wei Xiao
In the fermentation progress, fermentation parameters including the feed rate, induction temperature, and induction pH evidently regulate the accumulation of acetic acid generated by recombinant E. coli in the medium. The production of thermostable β-glucosidase (Tpebgl3) was increased by optimizing the parameters mentioned step by step. The optimal conditions were obtained with the highest enzyme expression (560.4U/mL) and the maximum DCW (65g/L) at the pre-induction specific growth rate of 0.2h(-1) followed by a post-induction specific growth rate (0...
May 22, 2017: Bioresource Technology
https://www.readbyqxmd.com/read/28627766/recent-applications-of-metal-organic-frameworks-in-sample-pretreatment
#5
Yonghua Wang, Min Rui, Guanghua Lu
Metal-organic frameworks are promising materials in diverse analytical applications especially in sample pretreatment by virtue of their diverse structure topology, tunable pore size, permanent nanoscale porosity, high surface area and good thermostability. According to hydrostability, metal-organic frameworks are divided into moisture-sensitive and water-stable types. In the actual application, both kinds of metal organic frameworks are usually engineered into hybrid composites containing magnetite, silicon dioxide, graphene or directly carbonized to metal-organic-frameworks-derived carbon...
June 19, 2017: Journal of Separation Science
https://www.readbyqxmd.com/read/28627549/self-assembly-of-silver-i-based-high-energy-metal-organic-frameworks-he-mofs-at-ambient-temperature-and-pressure-synthesis-structure-and-superior-explosive-performance
#6
Cheng Shen, Yang Liu, Zhong-Qin Zhu, Yuan-Gang Xu, Ming Lu
Two new high-energy metal-organic frameworks (HE-MOFs), {Ag2(DNMAF)(H2O)2}n (1) and {Ag2(DNMAF)}n (2) were prepared using potassium 4,4'-bis(dinitromethyl)-3,3'-azofurazanate (K2DNMAF) in a self-assembly strategy. Compound 1 exhibits a 3D HE-MOF structure with coordinated water molecules. Compound 2 exhibits compact solvent-free 3D HE-MOFs. Both compounds show good thermostability (decomposition temperature (Td) of 211 and 218 °C) and superior detonation velocities (D) of 9673 m s(-1) and 10 242 m s(-1), detonation pressures (P) of 50...
June 19, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28621786/alkali-and-alkaline-earth-metal-salts-of-tetrazolone-structurally-interesting-and-excellently-thermostable
#7
Piao He, Le Wu, Jin-Ting Wu, Xin Yin, Michael Gozin, Jian-Guo Zhang
Tetrazolone (5-oxotetrazole) was synthesized by a moderate strategy through three steps (addition, cyclization and catalytic hydrogenation) avoiding the unstable intermediate diazonium, as reported during the previous preparation. Alkali and alkaline earth metal salts with lithium (1), sodium (2), potassium (3), rubidium (4) caesium (5), magnesium (6), calcium (7), strontium (8) and barium (9) were prepared and fully characterized using elemental analysis, IR and NMR spectroscopy, DSC and TG analysis. All metal salts were characterized via single-crystal X-ray diffraction...
June 16, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28618113/the-mechanism-of-interactions-between-tea-polyphenols-and-porcine-pancreatic-alpha-amylase-analysis-by-inhibition-kinetics-fluorescence-quenching-differential-scanning-calorimetry-and-isothermal-titration-calorimetry
#8
Lijun Sun, Michael J Gidley, Fredrick J Warren
SCOPE: This study aims to use a combination of biochemical and biophysical methods to derive greater mechanistic understanding of the interactions between tea polyphenols and porcine pancreatic α-amylase (PPA). METHODS AND RESULTS: The interaction mechanism was studied through fluorescence quenching (FQ), differential scanning calorimetry (DSC) and isothermal titration calorimetry (ITC) and compared with inhibition kinetics. The results showed that a higher quenching effect of polyphenols corresponded to a stronger inhibitory activity against PPA...
June 15, 2017: Molecular Nutrition & Food Research
https://www.readbyqxmd.com/read/28616644/synergistic-hydrolysis-of-xylan-using-novel-xylanases-%C3%AE-xylosidases-and-an-%C3%AE-l-arabinofuranosidase-from-geobacillus-thermodenitrificans-ng80-2
#9
Di Huang, Jia Liu, Yanfei Qi, Kexin Yang, Yingying Xu, Lu Feng
Lignocellulosic biomass from various types of wood has become a renewable resource for production of biofuels and biobased chemicals. Because xylan is the major component of wood hemicelluloses, highly efficient enzymes to enhance xylan hydrolysis can improve the use of lignocellulosic biomass. In this study, a xylanolytic gene cluster was identified from the crude oil-degrading thermophilic strain Geobacillus thermodenitrificans NG80-2. The enzymes involved in xylan hydrolysis, which include two xylanases (XynA1, XynA2), three β-xylosidases (XynB1, XynB2, XynB3), and one α-L-arabinofuranosidase (AbfA), have many unique features, such as high pH tolerance, high thermostability, and a broad substrate range...
June 14, 2017: Applied Microbiology and Biotechnology
https://www.readbyqxmd.com/read/28615636/autotransporter-domain-dependent-enzymatic-analysis-of-a-novel-extremely-thermostable-carboxylesterase-with-high-biodegradability-towards-pyrethroid-pesticides
#10
Xianghai Cai, Wei Wang, Lin Lin, Dannong He, Gang Huang, Yaling Shen, Wei Wei, Dongzhi Wei
The EstPS1 gene, which encodes a novel carboxylesterase of Pseudomonas synxantha PS1 isolated from oil well-produced water, was cloned and sequenced. EstPS1 has an open reading frame of 1923 bp and encodes the 640-amino acid carboxylesterase (EstPS1), which contains an autotransporter (AT) domain (357-640 amino acids). Homology analysis revealed that EstPS1 shared the highest identity (88%) with EstA from Pseudomonas fluorescens A506 (NCBI database) and belonged to the carboxylesterase family (EC 3.1.1.1). The optimum pH and temperature of recombinant EstPS1 were found to be 8...
June 14, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28606536/preparation-and-characterization-of-poly-maleic-acid-grafted-cross-linked-chitosan-microspheres-for-cd-ii-adsorption
#11
Zhenzhen Yu, Qifeng Dang, Chengsheng Liu, Dongsu Cha, Haifeng Zhang, Wenjing Zhu, Qianqian Zhang, Bing Fan
A novel adsorbent, composed of poly(maleic acid)-grafted cross-linked chitosan microspheres (PMACCMs), was prepared via cross-linking with glutaraldehyde and modification by grafting maleic acid. FTIR, zeta potential, elemental analysis, (13)C NMR, DTG, laser particle size analysis, SEM, and BET methods were applied to characterize PMACCMs, exhibiting a successful fabrication, good thermostability, and well-defined surface microstructure beneficial to Cd(II) adsorption. The effects of pH, contact time, and initial concentration on Cd(II) adsorption were also investigated, and the maximum adsorption capacity was 39...
September 15, 2017: Carbohydrate Polymers
https://www.readbyqxmd.com/read/28600316/an-in-vitro-enzyme-system-for-the-production-of-myo-inositol-from-starch
#12
Tomoko Fujisawa, Shohei Fujinaga, Haruyuki Atomi
We developed an in vitro enzyme system to produce myo-inositol from starch. Four enzymes were used, maltodextrin phosphorylase (MalP), phosphoglucomutase (PGM), myo-inositol-3-phosphate synthase (MIPS) and myo-inositol monophosphatase (IMPase). The enzymes were thermostable; MalP and PGM from the hyperthermophilic archaeon Thermococcus kodakarensis, MIPS from the hyperthermophilic archaeon Archaeoglobus fulgidus and IMPase from the hyperthermophilic bacterium Thermotoga maritima Enzymes were individually produced in Escherichia coli, and partially purified by subjecting cell extracts to heat treatment and removing denatured proteins...
June 9, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28596548/sortase-a-mediated-crosslinked-short-chain-dehydrogenases-reductases-as-novel-biocatalysts-with-improved-thermostability-and-catalytic-efficiency
#13
Kunpeng Li, Rongzhen Zhang, Yan Xu, Zhimeng Wu, Jing Li, Xiaotian Zhou, Jiawei Jiang, Haiyan Liu, Rong Xiao
(S)-carbonyl reductase II (SCRII) from Candida parapsilosis is a short-chain alcohol dehydrogenase/reductase. It catalyses the conversion of 2-hydroxyacetophenone to (S)-1-phenyl-1,2-ethanediol with low efficiency. Sortase was reported as a molecular "stapler" for site-specific protein conjugation to strengthen or add protein functionality. Here, we describe Staphylococcus aureus sortase A-mediated crosslinking of SCRII to produce stable catalysts for efficient biotransformation. Via a native N-terminal glycine and an added GGGGSLPETGG peptide at C-terminus of SCRII, SCRII subunits were conjugated by sortase A to form crosslinked SCRII, mainly dimers and trimers...
June 8, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28593518/purification-characterization-and-retting-of-crotolaria-juncea-fibres-by-an-alkaline-pectin-lyase-from-fusarium-oxysporum-mtcc-1755
#14
S Yadav, S K Maurya, G Anand, R Dwivedi, D Yadav
Using solid-state fermentation, production of an industrially important pectin lyase from a fungal strain Fusarium oxysporum MTCC 1755 was attempted, which was further subjected to purification and characterization. The enzyme was purified by three steps, namely ammonium sulfate fractionation, cation-exchange chromatography on CM cellulose followed by gel filtration chromatography using Sephadex G-100 column. A 16-fold purification with 31.2% yield and 3.2 U/mg specific activity was achieved. The optimum pH of the purified enzyme was 9...
June 2017: 3 Biotech
https://www.readbyqxmd.com/read/28589227/laccase-mediated-synthesis-of-lignin-core-hyperbranched-copolymers
#15
Mark D Cannatelli, Arthur J Ragauskas
Lignin, one of the major chemical constituents of woody biomass, is the second most abundant biopolymer found in nature. The pulp and paper industry has long produced lignin on the scale of millions of tons annually as a by-product of the pulping process, and the dawn of cellulosic ethanol production has further contributed to this amount. Historically, lignin has been perceived as a waste material and burned as a fuel for the pulping process. However, recent research has been geared toward developing cost-effective technologies to convert lignin into valuable commodities...
June 6, 2017: Applied Microbiology and Biotechnology
https://www.readbyqxmd.com/read/28589226/the-first-acidobacterial-laccase-like-multicopper-oxidase-revealed-by-metagenomics-shows-high-salt-and-thermo-tolerance
#16
Luka Ausec, Francesca Berini, Carmine Casciello, Mariana Silvia Cretoiu, Jan Dirk van Elsas, Flavia Marinelli, Ines Mandic-Mulec
Metagenomics is a powerful tool that allows identifying enzymes with novel properties from the unculturable component of microbiomes. However, thus far only a limited number of laccase or laccase -like enzymes identified through metagenomics has been subsequently biochemically characterized. This work describes the successful bio-mining of bacterial laccase-like enzymes in an acidic bog soil metagenome and the characterization of the first acidobacterial laccase-like multicopper oxidase (LMCO). LMCOs have hitherto been mostly studied in fungi and some have already found applications in diverse industries...
June 6, 2017: Applied Microbiology and Biotechnology
https://www.readbyqxmd.com/read/28589224/molecular-engineering-of-l-aspartate-%C3%AE-decarboxylase-for-improved-activity-and-catalytic-stability
#17
Wanli Pei, Junli Zhang, Siying Deng, Fitsum Tigu, Yongxian Li, Qi Li, Zhen Cai, Yin Li
β-Alanine is an important precursor for the production of food additives, pharmaceuticals, and nitrogen-containing chemicals. Compared with the conventional chemical routes for β-alanine production, the biocatalytic routes using L-aspartate-α-decarboxylase (ADC) are more attractive when energy and environment are concerned. However, ADC's poorly understood properties and its inherent mechanism-based inactivation significantly limited the application of this enzyme. In this study, three genes encoding the ADC enzymes from Escherichia coli, Corynebacterium glutamicum, and Bacillus subtilis were overexpressed in E...
June 6, 2017: Applied Microbiology and Biotechnology
https://www.readbyqxmd.com/read/28587443/in-vitro-antimicrobial-potential-of-extracts-and-phytoconstituents-from-gymnema-sylvestre-r-br-leaves-and-their-biosafety-evaluation
#18
Daljit Singh Arora, Henna Sood
The in vitro antimicrobial screening of Gymnema sylvestre leaves against 13 test pathogens established its broad spectrum activity with average inhibition zone ranging from 14 to 23 mm. The antimicrobial activity of the classically- optimized aqueous extract was enhanced up to 1.45 folds, when subjected to statistical optimization using Response Surface Methodology (RSM) and was thermostable. Ethyl acetate was found to be the best organic extractant with Klebsiella pneumoniae 1 (31.5 mm) and Staphylococcus epidermidis (25...
December 2017: AMB Express
https://www.readbyqxmd.com/read/28585068/a-novel-nitrilase-from-ralstonia-eutropha-h16-and-its-application-to-nicotinic-acid-production
#19
Haiyang Fan, Lifeng Chen, Huihui Sun, Hualei Wang, Yuhong Ren, Dongzhi Wei
A novel aliphatic nitrilase, REH16, was found in Ralstonia eutropha H16 and overexpressed in Escherichia coli BL21(DE3), and its enzymatic properties were studied. The temperature and pH optima were 37 °C and 6.6, respectively, and the best thermostability of the nitrilase was observed at 25 °C, which preserved 95% of activity after 120 h of incubation. REH16 has a broad hydrolytic activity toward aliphatic and heterocyclic nitriles and showed high tolerance of 3-cyanopyridine; this enzyme could hydrolyze as high as 100 mM 3-cyanopyridine completely...
June 5, 2017: Bioprocess and Biosystems Engineering
https://www.readbyqxmd.com/read/28583872/targeted-mutations-and-md-simulations-of-a-methanol-stable-lipase-ylip9-from-yarrowia-lipolytica-msr80-to-develop-a-biodiesel-enzyme
#20
Poonam Syal, Ved Vrat Verma, Rani Gupta
Biodiesel, an environment friendly alternative for fuels, contains methyl esters of long-chain fatty acids. Our group has reported a methanol-stable YLIP9 from Yarrowia lipolytica MSR80 that shows poor catalysis of long-chain fatty acids. To shift its substrate specificity, residues within lid and binding pocket were identified for sequential mutations using YLIP2 as the template. Of the two point mutations (Glu116Leu and Ser119Val) introduced in the lid, the former mutation (YLIP9L1) increased the catalytic rate by ∼2-fold without any change in substrate specificity...
June 2, 2017: International Journal of Biological Macromolecules
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